Apr 7, 2010 · Hashmap is used for storing data in key value pairs. We can use a hashmap for storing objects in a application and use it further in the same application for storing, updating, deleting values.

What are the differences between a HashMap and a Hashtable in Java? Which is more efficient for non-threaded applications?

What is the difference between HashMap, LinkedHashMap and TreeMap in Java? I don't see any difference in the output as all the three has keySet and values. Also, what are Hashtables? …

Apart from the fact that HashSet does not allow duplicate values, what is the difference between HashMap and HashSet in their implementation? It's a little bit vague because both use hash tables to...

Jul 1, 2009 · Since all maps in Java implement the Map interface, the following techniques will work for any map implementation (HashMap, TreeMap, LinkedHashMap, Hashtable, etc.) Method #1: …

Map<String, String> myMap = new HashMap<String, String>() {{ put("a", "b"); put("c", "d"); }}; However, the anonymous subclass might introduce unwanted behavior in some cases. This includes for …

Jul 7, 2009 · I need to convert a HashMap<String, Object> to an array; could anyone show me how it's done?

64 Map is an interface that HashMap implements. The difference is that in the second implementation your reference to the HashMap will only allow the use of functions defined in the Map interface, while …

HashMap<String, String> servicesNameHashmap = new HashMap<String, String>(); in your for loop. It will have same effect like same key and multiple values.

Apr 27, 2013 · Convert Hashmap to MapSet to get set of entries in Map with entryset() method.: Set st = map.entrySet(); Get the iterator of this set: Iterator it = st.iterator(); Get Map.Entry from the iterator: …